


Changes with Growth

by ThePhoenixWriter



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Claude be a growing boy, Consensual but has to be mentioned, Creampie, F/M, Female My Unit | Byleth, I havent finished the golden deer route so be gentle :'), Past Underage Sex, Post-Time Skip, Referenced Underage Sex, Size Difference, Spoilers, also this is mostly to quench my Claude thirst and size difference kink thankssss, but mostly minor :/ read at your own risk, fuck protection am I right, long as you know about the dance pre time skip and theres a time skip you fine
Language: English
Status: Completed
Published: 2019-08-15
Updated: 2019-08-16
Packaged: 2020-09-01 18:35:38
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 3,417
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20262658
Author URL: https://archiveofourown.org/users/ThePhoenixWriter/pseuds/ThePhoenixWriter
Summary: Byleth meets Claude again after the time skip.The only thing she didn't expect was to be looking up to him, and how much he had grown in a few years. And the fact he had been waiting for her.





	1. Reunion

**Author's Note:**

> Hey guys! This is my first fan fiction for Three Houses and I just got to the time skip in the Golden Deer route. 
> 
> I just had to write Claude and I felt size kink would fit with the skip. 
> 
> Also: Make sure to leave comments and kudos, it helps me keep motivation to write!
> 
> Taking free fanfic requests or any other questions here: https://curiouscat.me/ThePhoenixWriter

Claude couldn't explain how happy he was to see Byleth again.

After the years of waiting and not knowing her whereabouts, whether she was dead or alive, he felt like laughing or crying when seeing her again. She seemed to not have aged, her hair still its same color and expression as calm as ever. However he could see in her eyes the spark of joy that hid in them, happy to see her student again.

Though, Claude did remember the times at the monastery where they were more than that. 

He can see himself yet again as a near adult, with his professor sneaking Claude into her room for sessions of love making. He was thankful no one caught them, though the disapproving looks he occasionally got from Lorenz at the dining hall did worry the archer. Or the way the other deer members would glance at him told him that their group wasn't completely unaware something was going on between them. Hopefully though it never went past rumors or speculation into actual knowledge of their whereabouts. 

He knew he had discussed with Byleth how he wanted a relationship once he was graduated and able, which she was more than on board with. Though, the skip in time and hardships he faced made him wonder if his former professor longed for the same thing anymore, or changed into someone different than what he once knew. It made him nervous, now that they returned to the monastery with their old classmates in tow. 

He knew it was something he couldn't discuss with his classmates there, as their previous relationship had been kept secret, but questions about what they were raced through his mind. He knew at a time like this with battles ahead there were more pressing matters, but Byleth was what really mattered to him. After all, he had waited for her the last half-decade.

Claude returned to his old room once things had been restored, glad to put his stuff down. He was hoping after dinner to maybe talk with Byleth in private, after he had been staring holes into the back of her head on their way back to the school. He knew he wanted to make things right again and reconnect, but he felt things had changed. 

Especially when he looked at her. 

Claude remembers how as a teen he was smaller than Byleth, having to look up to meet her eye. It was definitely a difference of height by a decent margin, but he always felt frustrated about being shorter than her. Especially when he visited her at night, with him usually being ridden to compensate for the height or missionary being their normal positions. He always wanted to fuck her against a wall but often Claude couldn't get the right leverage, along with doggy proving difficult considering his hips were to low to meet properly up with hers.

Though, seeing her again made him realize how time had been kind to him, having grown over a foot in the past few years. He was now taller than Byleth by a head. He roughly stood a little over 6 feet, with her a little under five and a half feet herself.

He smiled to himself at the fact at dinner, having to now look down instead of up to see her gorgeous eyes.

He sat next to her, glad to grab the dishes of food out of her reach at the table, able to snatch them with ease and pass them to her, which she gratefully accepted. He even smirked at the fact when passing off the bowls how easily her hands could fit in his, and how he had surpassed her so easily in height. He was also happy at the fact Byleth held onto his hands a little too long when offered the dishes, and often found her leaning over him to grab something trivial on the table. Lorenz though seemed aware of the lingering touches and stares between them as the group ate, and it didn't escape Hilda's or Leonie's watchful eyes either. 

Lorenz commented nonchalantly, picking at his plate, "So, when is the wedding?"

Claude nearly dropped the fork in his hand at the question, while Byleth stopped mid-sip of her drink.

"Excuse me?" Claude snorted, trying to laugh off the jest. 

As a noble and having recently reunited, he was hoping he could wait until after the war and especially after he discussed his relationship with Byleth. He didn't know where they stood, but based on her gestures and the way she warmed up to him, it was obvious both held feelings for each other after the years. Still, he was a noble and his concerns should be for the Alliance at the moment, not his love life. More importantly, if their relationship was revealed now, it would be obvious them being a couple happened while he was still a student at the monastery. 

_This is bad, I've gotta handle this, _Claude thought to himself.

Hilda chimed in, taking another scoop of her dessert, "I hate to say it Claude, but Lorenz is right. You're really obvious about liking Professor." 

Claude replied cooly, "So I care about Teach, just like the rest of you. Nothing more. After all, I can't be the only one who got concerned after she disappeared like that."

Lorenz scoffed, "As students, I don't think any of us cared enough to make late night visits after curfew."

Claude could feel himself starting to heat up in the face, his leg bouncing underneath the table as he tried to keep his cool. The rest of the table that were having side conversations seemed to have quieted to a lower tone, including everyone but Byleth, Claude, Lorenz, and Hilda. They did their best to not make it silent or tense by talking quietly, but still were listening in to the debate. 

"Sorry to say Lorenz, but that's a wild accusation for someone I know wouldn't go out that late himself. Besides, I always snuck out for plenty of different schemes. So it has nothing to do with Teach."

Lorenz laughed, "True, I wouldn't cause trouble at night unlike you, Claude. But I tend to wake earlier than most and I can count several occasions of seeing you leave the Professor's quarters right before dawn. That, I'm afraid, is something I don't think is explainable other than for an obvious reason."

Claude feeling cheeky, smirked. "Discussing strategies? You must be jealous you weren't invited."

Byleth elbowed him in the side, making the archer shift in his chair. He often was used to being provoked by royals with different ideals and plans, some more openly rude than others. Claude as a leader was always able to keep his cool, but it was rather hard as Byleth was being dragged into this and it was his close friends. He never had been accused of romantic affairs, so keeping his facade of not caring was rather hard all things considered. Also the look Byleth had was calm to any onlookers, but Claude could tell she was beginning to let her nerves go too as she gripped her right thigh with her hand.

Leonie then joined in, "We would support you two as a couple, Professor. Lorenz is just a little less sensitive about these things is all."

Raphael nodded, finally deciding to talk himself, "That we would! We'd be happy to throw a feast to celebrate you two getting together."

The table all then seemed to murmur agreements about it, making Claude feel a little less uncomfortable about the whole thing. Though, they never were officially a couple. It just sort of happened one night and they kept the late night meetings going. So he wasn't sure he wanted to come out in full support in case Byleth wasn't looking to court and put her in an uncomfortable spot. It wasn't his place to fully go with his classmates, so he looked to Byleth for her to respond. 

She sighed, eventually speaking up in a soft tone. "Alright. Me and Claude are a thing."

The archer could already see where this was going, knowing full well they were going to tease everything out of them. They were all adults now, and good friends by this point. So he was for sure they were going to ask every question and jest him for everything and anything. He was proud though that Byleth said they were together in a way, smiling that she still said are instead of were. 

Hilda grinned, "Oh do tell, Professor! I'm sure we'd all love to hear how sappy Claude is."

Lorenz whined dramatically, "I have to respectfully disagree. Claude being even the _slightest_ hint of romantic sounds like an awful thing to endure! Truly our professor has nerves of steels to survive that kind of torment. How sad a woman has to make such a sacrifice for the rest of her kind."

Leonie teased, "Well, I think Lorenz is right that way. I'm sure Claude's idea of an ideal date is scheming together or concocting some mild poisons." 

Claude retorted, mildly offended by the jabs, "I can be romantic! I'll let you know I actually cooked Teach a proper meal."

Leonie sarcastically replied, "A noble cooking a meal. Let me guess, seasoned charcoal?" 

The night then went on into poking fun at Claude and the group joking about on other topics. Claude was happy the night went well, with all in attendance jovial at the news that Byleth and Claude were a couple. It left them in high spirits considering the bleak situation around them, and everyone felt their cares wash away for the night. 

He was happy to see everyone relax, but soon the night winded down after drinks and good talk. Everyone started to walk back to their respective rooms, content with a good meal and even better company. Claude walked to his room, waiting until the chatter outside simmered to nothing but the sounds of the night. He then snuck out of his room, quietly making his way to Teach's room.

Claude chuckled to himself, remembering his younger days of sneaking like this. Though, he had little to fear this time. It wasn't exactly needing to keep a secret of what he was doing. 

He was glad to knock and find the door unlocked, Byleth sitting on the bed waiting for him.

"Hello, Claude." 

"Hey, Teach." 


	2. Remembering

**Summary for the Chapter:**

> Basically Claude gets the goods ;)

**Notes for the Chapter:**

> Hey guys! This is my first fan fiction for Three Houses and I just got to the time skip in the Golden Deer route.
> 
> I just had to write Claude and I felt size kink would fit with the skip.
> 
> Also: Make sure to leave comments and kudos, it helps me keep motivation to write!  
And I'd like to add that I am slightly drunk and it is nearly 3 AM so any errors or mess is because I am sleep deprived and had a few cokes and whiskeys :')

Claude walked up to her, leaning down for a kiss. 

Byleth happily returned the gesture, wrapping her arms around his neck. The kiss lingered, then they kissed again, and then things started heating up. Claude lifted his former teacher to wrap her around his waist, keeping both hands under her ass to support her weight as her legs curled around his waist, with the bowman content as Byleth kissed him madly. He knows his past self would be nearly hollering with joy to see how he could now easily tower over his mentor.

Claude can't admit how much he had missed this, how the last five years were spent alone at night remembering of her. He hates to think how many nights he jerked off looking back to those memories of fucking his teacher, and to have her back now with such a size advantage was goddess sent. He growled and nipped into her neck, trying to illicit some moans out of his lover. He planned to savor this for all he could get, he had five years of frustration to get out tonight. 

"The others, Claude!"

The mercenary hissed out, her emotions finally coming out like they used to in the bedroom.

"_Fuck _the others, I've been waiting five years for this Teach and I fully intend to leave you so sore you can't walk tomorrow." 

Byleth felt her body shiver at his dirty talking, knowing he was full well going to live up to that promise. She tugged at his shirt, which he frantically removed and began to tug back at hers. She was more than happy to comply, dropping the shirt unceremoniously to the floor. Clothes soon began to pile below them, Claude eventually using his strength to push his former professor against one of the walls. He and Byleth were now down to underwear and nothing more, longing for the contact of skin they had both been missing. Claude adored how curved and perfect Byleth had stayed through the years, and he felt satisfied of how he developed as well. Byleth roamed her hands over his chest, admiring the chest hair and way his body had filled and toned over the past five years. She looked over his torso with lidded eyes, humming in approval about the change. 

Claude really had been wanting to make love to Byleth ever since they reunited, and she seemed eager based on the wet spot dripping from her panties onto his briefs. They were both wet from slick and pre cum, but he could hear Byleth moaning and whining under him. He finally set her down on the bed, letting her sit upright while he stood next to her. She undid his pants, Claude panting in anticipation as she revealed his cock completely erect. 

"Oh goddess," Byleth breathed out.

"You alright there, Teach?"

"You weren't this big before."

Claude blushed, looking down to realize that he probably had grown both in height and in other proportions of his body. Especially when realizing how much larger he was than Byleth, his height may be a blessing or a curse if he nearly ripped her in half when he tries to push in. Still, it made him proud she was so impressed. She started to prep him by lubing him up, kissing the tip open and wet. He shivered at the sensation, and nearly shaking his legs when Byleth finally wrapped her lips around his dick. 

The nobleman moaned and pushed his lover down farther on his cock, putting both his hands on either side of her face. Claude could at first hear his lover slightly gagging on his cock, but she adapted quickly and began to bob down on him. He then murmured soft praises to her between pants and moans as he gripped her green hair, Byleth getting into a rhythm. Claude loved to look down on Teach who had tears forming at the corner of her eyes and her jaw straining to fit his width. He really could stay like this forever, his body shivering as Byleth swirled her tongue around his girth and covered it in her drool. Though, he felt he wouldn't last long with such divine treatment. It had been years of frustration and only his hand to help him, so to have a gorgeous mouth entrapping his dick was proving too much for him.

"Teach, fuck- I'm not gonna be treating you tonight if you keep this up. I'm gonna cum," Claude gritted out between his teeth.

Thankfully Byleth was merciful and removed herself, proud of her work as Claude's cock had a wet sheen on it from her blowjob. Claude rewarded her with a gentle kiss on the forehead and massaging her chin and neck for taking so much. 

Claude then climbed onto the bed himself, glad to lay Byleth on her back and set himself between her milky thighs. He loved the view of her pink cunt, begging for attention and awaiting him. Claude kissed her folds softly before diving in, lapping eagerly around her pussy. His teacher wriggled underneath him, moaning and reaching a hand down to ground itself in dark, messy hair. 

Claude was always good at oral. Even from their first session Byleth always commented how talented he was with his tongue, and his ability to listen to her commands. He then focused on sucking her clit, bringing two fingers to her entrance. He knew with how small she was in comparison to him that Byleth was going to struggle to fit his cock, so anything to stretch or lube her was his first priority. Claude could tell that she was soaking wet, as his chin was drenched with her cum. He inserted another finger, watching as she squirmed on the digits spreading her from the inside.

After a few moments, Byleth pulled Claude's hair back in a harsh shove, making him hiss in pain from the sudden tug. He looked up to see her hair tousled, face red, with her breathing uneven, which was a stunning sight to know he unraveled her like this. 

"I'm done waiting. I want you to _fuck me, _Claude," Byleth growled.

The man in question nodded, not needing any more instruction. 

Claude then positioned himself on top of Byleth in missionary style, spitting in his hand and stroking his dick to get it slicked up. He wanted to use oil, but he had no intention to go searching for it in his professor's quarters. He had waited long enough as is for this moment. 

Byleth gasped when Claude slid himself in, going as slow as his body would let him. It felt like coming home for him as the familiar wet warmth enveloped him, tighter now as he stretched her further, and nothing had ever felt better in his life. Claude wanted to give Byleth time to adjust, as he felt her shaking underneath him, but every muscle in his body screamed for him to move. He knew she had probably never felt so filled before, and it was showing based on how rough she was clawing at his back with her arms wrapped around him. He had to be patient even if it killed him. And even if it cost him his back, which he was sure would be bloody and scratched to all hell by the end of the night. 

"You alright, Teach?" Claude whispered into her ear, stilling himself once halfway in.

Byleth spoke back through gritted teeth, "I'll survive, just start moving."

"Y'know I won't be able to stop once I get started-"

Claude didn't get to finish his sentence as Byleth began to move her hips, frustrated with how hesitant he was being. It was an obvious demand to get to work, and Claude was more than obedient and willing to follow her orders. He slammed himself in, smug when his professor nearly screamed out from the unexpected movement. He then set himself into a rhythm, gripping the bedsheets as he plowed Byleth into the mattress. He rested one hand down between her legs, rubbing at her clit with his thumb. Byleth was a moaning mess at this point, and Claude was determined to let her finish first. He knew his orgasm was fast approaching, especially with her clenching down like a warm vice. But, Claude wanted to outperform his previous self, who as a teen could never outlast his professor.

It soon proved a losing fight for Claude, his hips starting to stutter in their movement and his dick was throbbing for release. Byleth must have been feeling it too, as she wrapped her legs around his waist to try and keep her partner steady. 

"_Shit,_ Byleth, where-?"

"-Inside."

Claude nearly lost it there at the suggestion, but he stopped himself. It really was a big risk considering their statuses, but at this point Claude couldn't care less. He thrusted a few more times and then held himself flush against Byleth's hips, emptying himself inside. Claude moaned and nestled himself into Byleth's shoulder, nearly shaking from the intensity of cumming so hard. He kept still until he had completely finished, pulling himself out and laying beside his lover. 

Byleth rested her head on Claude's chest, holding hands with him as they both caught their breaths. He kissed the top of her head, content to finally lay with her like this after all these years. 

"Sorry you didn't finish," he murmured in apology.

Byleth shifted herself on her side, looking up to meet his eyes. _Fuck, _Claude thought, _I really love those green eyes. _Seeing her look at him like he created the world make Claude realize how lucky he was to have Byleth by his side. He wanted her to be there always, through the worst and the best parts of his life, and he didn't know how he survived this long without her. 

"It's fine, my sweet. There's always next time," Byleth replied. 

Claude chucked, "That is true, I guess. I look forward to it." 

"I love you, Claude."

"Love you too, Byleth." 

**Notes for the Chapter:**

> Hope you guys enjoyed! I do take free requests if the prompts interest me and I feel I can do the idea justice. No promises if I'll do requests but don't hesitate to leave a comment with an idea!!

**Author's Note:**

> Hope you guys enjoyed! I do take free requests if the prompts interest me and I feel I can do the idea justice. No promises if I'll do requests but don't hesitate to leave a comment with an idea!!


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